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Mr. Glen L. Foster October 4, 2007 Page 2 _ PEA Report Review The PEA Report investigated soil and groundwater at three (3) Areas of Concern (AOCs) at the Site for metals, volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), cyanide, pH and Total Recoverable Petroleum Hydrocarbons (TPPH). The soil investigation found that metals were within the background concentration, except for lead and arsenic. Lead, with a maximum concentration of 1210 mg/kg, exceeded background and the residential California Human Health Screening Levels (CHHSLs) of 150 mg/kg. Elevated levels of lead exceeding CHHSLS were found in the Plating Process and Bulk Storage Tank areas. Low levels of VOCs, SVOCs and TRPH were detected at the Site however they were all below the human health screening levels. The groundwater investigation found the following: maximum nickel concentration of 0.794 mg/I exceeding the California Maximum Contaminant Level of 0.1 mg/I; 37 ng/I of N-Nitrosodimethylamine (NDMA) exceeding the California Notification Level of 10 ng/I.; and maximum concentration of 16 ug/I Methyl Tertiary Butyl Ether (MTBE) exceeding the California Primary MCL of 13 ug/I. The PEA Report risk evaluation determined that under the residential exposure scenario, the total cancer Risk based on maximum concentrations of chemicals of potential concern (COPCs) in soil without chemicals detected in groundwater below their MCLs is 2.5x10-5; and with a Hazard Index of 9.6 for a child and 2.5 for adult. The total cancer Risk based on 95% UCL concentration of COPCs in soil and without chemicals detected in groundwater below their MCLs is 1.8x10"5, with a Hazard Index of 2 for a child, and 0.7 for adult. Based on the above results, DTSC concurs with the conclusion of the report that a deed restriction is necessary at the Site. However, due to the elevated levels of contaminants in groundwater exceeding the MCL, DTSC suggests that groundwater monitoring is necessary to address the groundwater contaminants exceeding regulatory levels. DTSC suggests that a groundwater workplan be submitted to DTSC for review and approval. The workplan should include a quarterly groundwater monitoring for at least a minimum of one year. The PEA Report also identified that 2-10% Chrysotile type asbestos was found in the roof caulking materials at the site, exceeding the 1.0% limit regulated by United States Environmental Protection Agency (U.S. EPA). DTSC concurs with the PEA Report in that any asbestos-containing material that may be damaged or disturbed during a renovation or construction project should be abated and disposed of properly in compliance with the requirements of the National Emissions Standards for Hazardous Air Pollutants regulations from U.S. EPA, and the State laws.